i would recommend having a batch of sw mixed up just in case, and to make sure that you have enought to fil your tank. i would premix some salt using ro water about 24 hours in advance. you will need a powerhead in the water to circulate it and to dissove all the salt. make sure that it is at the correct salinity for your new tank. i also add an airstone to my water as this alllows for good aeriation, and also helps in circulation. make sure the water is the same, temp, pH and salinity before adding it to the tank and you are all set!
good luck
jon